In U.S. Pat. No. 3,466,077 there is illustrated a one-piece all plastic seal, which comprises a cylindrical housing open at one end only, a group of resilient fingers disposed about the inside surface of the housing and having flexible ends extending toward the closed end thereof, and a shackle integral with the housing at one end, the distal end thereof having a shouldered stud adapted to be inserted into the open end of the housing, whereupon the resilient fingers lock behind the shoulder of the stud, so that attempted disengagement of the stud from the socket causes fracture of the shackle.
It has been found that with sufficient time available and with the proper instrument, such as a thin flexible blade, the seal as described in the above identified patent can be opened without substantial evidence of tampering. This may be accomplished in one manner by inserting the blade into the housing between the stud and the housing wall. With a tool of proper shape, one or more of the resilient fingers may be flexed outwardly and possibly sideways for enough to cause the plastic at the root of the finger to lose strength and resiliency, after which it may stay in the outermost position, out of engagement with the stud. After the tool is withdrawn, the stud may then be pushed sideways in the housing far enough to dis-engage it from the finger or fingers on the other side of the housing, and the stud can then be withdrawn. On re-insertion of the stud, it will re-engage the remaining fingers and appear to be securely locked, and hence the container will appear to be secure.
In another manner, a portion of the closed end of the housing may be cut off and the fingers manipulated to release the stud. Thereafter the cut-off portion can be replaced by adhesive, and the stud re-assembled after the container protected by the seal has been rifled.